A problem frequently recurring in engineering is to releasably interconnect rotationally symmetrical parts. Clamping connections are frequently used for this purpose based on frictional transmission of forces. In such cases, spring forces, fluid pressure devices, or simple screw connections, apply a clamping force which, by acting on friction surfaces, ensures that the two parts are connected so as to rotate with one another. Very high forces are necessary in some cases to maintain the connection and secure the relative position of the two parts. Consequently, ordinary clamping elements are unsuitable or else the requirements that the clamping elements must satisfy are of such high specification that in some cases uneconomical connecting elements have to be used.
In printing engineering it is known, for example, to dispose double gearwheels in the transmission line of sheet-fed rotary presses so that sub-units of the press can be displaced relative to one another. In a double gearwheel of this kind, a gearwheel ring is fitted on a main gearwheel and is clamped fast there by means of clamping elements. The latter must ensure that the relative position between the gearwheel ring and the main gearwheel is maintained even under maximum stress. In some cases the clamping connection is in the form of a simple pressure connection, the friction surfaces between the gearwheel ring and the main gearwheel being used for the force transmission. Typically, the peripheral forces are applied by normal forces of appropriate value. For this purpose, strong springs and a corresponding number of clamping screws are required.
One approach to such an arrangement is described in DE-A1 38 20 026. As shown in this references, the gear ring is coupled to the main gearwheel via a connection in the form of a disc clutch in order to provide a non-positive connection between a fixed gearwheel and a movable gearwheel on a cylinder of a turn-over mechanism in a sheet-fed rotary press. The clutch discs are mounted at the end face of the main gearwheel and clutch discs are also provided concentrically thereof on the gearwheel ring and engage in the spaces between the clutch discs on the main gearwheel. In the region of the overlap, a clamp ring is fitted on the clutch discs and can be clamped relative to the main gearwheel. As a result, the clutch discs are clamped together and the gearwheel ring is frictionally connected to the main gearwheel.
Unfortunately, the entire arrangement of the foregoing reference makes the construction of the double gearwheel relatively complex. Also, there is no safeguard that the frictional forces will be uniformly distributed over the entire periphery. In addition, the construction is expensive due to the large number of parts.
A mechanism for deforming a gearwheel is known from DE-C1 3834429. This reference describes a gearwheel whose hub can be deformed by tensioning elements in order to change the diameter. However, it is not possible to secure the gearwheel with this mechanism.
It is the primary aim of the present invention to provide a clamping mechanism which enables a reliable and secure frictional connection to be achieved between relatively rotatable components of a gear drive.
A related and important object is to provide such a frictional clamping mechanism which achieves a secure connection in a relatively simple manner with greatly reduced forces.
It is also an object of the invention to provide a frictional clamping mechanism that employs only a few parts that may be made relatively economically.
In accordance with the present invention, a clamping mechanism is provided for securing together two radially adjacent concentric components of a gear drive, such components including, for example, a toothed gear ring, a gearwheel, a hub and a shaft. An annular recess is formed in the gear drive component and defines at least one circumferential and one radial wall. A substantially conically shaped convex clamping disc having a plurality of circumferentially spaced apertures is disposed in the annular recess. A plurality of tensioning bolts cooperate with the apertures in the clamping disc and threaded bores in the annular recess to compress the clamping disc and urge its peripheral edges radially into frictional engagement with the concentric gear drive components and axially into frictional engagement with the radial wall of the annular recess.
A particularly advantageous feature of the clamping mechanism of the present invention is that there is not just one friction surface in the axial direction, but also at least one other one directed radially to the gearwheel. Depending on the specific arrangement, two radially directed friction surfaces may be provided, thus enabling the transmissible torques to be additionally increased. Furthermore, the release forces required for tensioning elements of this kind are reduced in comparison with purely screw or spring connections. The conical arrangement of the tensioning element results in differences in clamping forces at the periphery of the gearwheel being substantially uniform. Assembly and removal of the gearwheels or gearwheel rings are also greatly simplified. The mechanism can be used with a direct or indirect action. In addition, the radial tensioning surfaces may optionally be used separately or else the radial and axial tensioning surfaces can be used jointly. Finally, in combination with the tensioning effect, it is also possible to deform the gearwheel ring to correct production errors.
These and other features and advantages of the invention will be more readily apparent upon reading the following description of the preferred embodiments of the invention and upon reference to the accompanying drawings.